In many industries, laboratories and hospitals cylinders of compressed gas are routinely used. Commonly multiple cylinders are stored side by side in an upright position and lines are run from a pressure regulator mounted on the cylinder gas outlet to the point of usage. A manual valve integrally mounted on the cylinder is opened to supply gas to the pressure regulator and thence to the user system. If the manual valve is left in the open position even a small leak ahead of the user end point valve will dissipate contents of the cylinders. When using hazardous gases, even small leaks are objectionable. Further, in cases where a hazardous gas is used, remote opening of the manual cylinder valve and closing it when not in use makes for a safer installation. Any remotely activated device to open the manual cylinder valve should be small enough to allow normal storage and hook up of manual valve cylinders in their usual side by side upright position. A device to protect the cylinder valve from breaking off the cylinder in the event the cylinder falls over is desirable. Further, any remotely activated device should be "fail-safe"--that is it should close the manual valve if power to operate the device fails. In this invention the power to operate the device, which we call a "pneumatic gas cylinder valve actuator" is air pressure to open and spring loading to close. Gas pressure opens the valve and spring loading closes the valve. Details of operation will become clear in the remainder of the specification and claims.
The simple installation of a small device as described to remotely open and close the gas cylinder valve would fill a need in the industry.
We have considered patents:
U.S. Pat. No. 3,570,373 issued to W. E. Tupkor 3/16/1971, PA1 U.S. Pat. No. 3,818,808 issued to H. J. Shafer 10/19/1972, PA1 U.S. Pat. No. 4,094,231 issued to Paul Carr 6/12/1973, and PA1 U.S. Pat. No. 4,392,631 issued to J. J. DeWald 7/12/1983 PA1 (a) to have a rugged small size pneumatically operated actuator to open and close a gas cylinder valve; PA1 (b) to have an actuator as described easily mounted to the cylinder; PA1 (c) to have an actuator as described that closes the gas cylinder valve in case of loss of air pressure or when air pressure is vented from the air line used to activate the actuator; PA1 (d) to close the manual valve sufficiently to close off flow but not to "jam" the valve closed. This is necessary to prevent need for excessive force to open the valve; PA1 (e) to have an actuator so mounted and designed as not to create a hazard if a cylinder accidently falls with actuator in place.
that are in the general field and also industrially available automatic operators. None of these satisfactorily fills the need for a small size, "fail-safe", easily mounted actuator that protects the gas cylinder valve in the event of a fall and opens and closes a gas cylinder valve when activated from a remote point.
Among the objects of this invention are:
The inventions involve proper sizing and positioning of components to fit in an actuator valve body no more than about 4 inches thick, 8 inches wide and 10 inches long and a positional clamping means to adjust closing torque on the gas cylinder manual valve while fastening simply on threads normally available on the gas cylinder. Piston size is such as to provide sufficient force with available air pressure of up to 100 psi above the pistons to open the gas cylinder valve while compressing springs under the pistons to close the gas cylinder valve when air pressure above the pistons is released. The position of the actuator valve body above the manual valve being opened and closed is critical because the travel of pistons is limited and the position determines compression of springs under the pistons when the actuator is engaged with the gas cylinder valve. The pistons have piston rods called gear racks intermeshed with a flat operator gear within the actuator valve body to translate piston motion to open and close the manual cylinder valve. At the time pressure above the pistons acts to open the cyllinder manual valve the springs under the pistons must be compressed sufficiently so that when air pressure above the pistons is released, the springs close the valve firmly. We have found a closure to about 70 inch pounds torque works well. After positioning the pneumatic valve actuator to vertically engage the valve wheel gripper of the actuator with the manual valve when the manual valve is closed, rotation of the body of the actuator is used to set the axial position of the actuator relative to the manual valve to compress the springs under the pistons in the actuator and a specially designed positional clamp is used to clamp the actuator to the threads on the gas cylinder used for threading on the protective cap during transport.